For hybrid electric vehicles with EV mode (purely electric driving), a startup of the internal combustion engine automatically occurs for a remaining electric range of travel of 0 km. In this case, it often happens that a startup of the internal combustion engine occurs a few meters just before the vehicle is parked. This is detrimental to the internal combustion engine and the environment and aggravating for the vehicle operator.
Against this background, the present invention is based on the object of preventing such situations.
Disclosed in US 2017/008513 A1 is a control unit for a hybrid vehicle, with which the hybrid vehicle prevents a startup of the internal combustion engine in specific situations in order to avoid the creation of noise. Such situations can be, for example, the presence of pedestrians in the vicinity of the vehicle, certain times of day, certain locations or zones, such as parking garages, narrow streets, or the vicinity of the dwelling of the driver. The vehicle recognizes the situations via sensors, timers, or GPS.
U.S. Pat. No. 6,283,086 B1 discloses a motor control unit for a hybrid vehicle, for which the hybrid vehicle recognizes when it is situated in a zone with traffic congestion and prevents a start-stop operation of the internal combustion engine in the traffic congestion.
EP 2 363 312 A2 teaches a control system for a hybrid vehicle, which starts the lubrication system of an internal combustion engine of the hybrid vehicle on the basis of data about the surroundings and the location and provides for a constantly good lubrication of the internal combustion engine even after a prolonged period of inactivity.
The known systems do not take into consideration the state of charge of the traction battery of the hybrid vehicle. When the indicator for the remaining range of travel of the electric drive drops to zero, the internal combustion engine of the vehicle is started even when this is, in fact, not desired.
However, an indication of a remaining range of travel of 0 km does not mean that the battery is completely discharged. In order to optimize the service life of the HV battery, only a portion of the battery capacity is utilized—for example, 20 to 80% of the total capacity. For an indication of a remaining range of travel of 0 km, the HV battery is therefore still charged, for example, to 20%. In accordance with the invention, the service life of the HV battery is weighed against the service life of the internal combustion engine and, in special cases, the battery is “overloaded” in order to prevent a startup of the internal combustion engine and thereby to protect the internal combustion engine and the environment.